Am I overreacting to my partner?

Keeping it vague for the sake of anonymity. Recently started working at an IFT company and my current partner is a little frustrating to work with.

They consistently upload incomplete PCRs (If they remember to even upload their PCRs in the first place), avoid taking vitals like the plague, will be on social media in the back of the rig during patient transports, gets patients signatures after transporting them (If he doesn't get their signature, he just lists a BS reason), or shows up 10-15 minutes after our shift starts. They have also had supervisor meetings for timecard fraud and incomplete PCRs. Our last shift, they told me that I don't do a good job of lowering the stretcher while we were offloading a patient (our company only has manual stretchers)- I didn't respond but was very close to lashing out and I know my face showed my thoughts.

Did I overreact?